clipline_test.go

package polyclip

import (
	"fmt"
	"reflect"
	"testing"
)

func TestClipLine(t *testing.T) {
	subject := Polygon{{
		{0, 1}, {1.25, 1}, {1.5, 1.1}, {1.75, 1}, {5, 1},
		{5, 2}, {0, 2},
	}}
	clipping := Polygon{
		{{1, 0}, {4, 0}, {4, 3}, {1, 3}},
		{{2, 0.5}, {3, 0.5}, {3, 2.5}, {2, 2.5}},
	}
	r := subject.Construct(CLIPLINE, clipping)
	want := Polygon{
		Contour{Point{X: 2, Y: 1}, Point{X: 1.75, Y: 1}, Point{X: 1.5, Y: 1.1}, Point{X: 1.25, Y: 1}, Point{X: 1, Y: 1}},
		Contour{Point{X: 2, Y: 2}, Point{X: 1, Y: 2}},
		Contour{Point{X: 4, Y: 1}, Point{X: 3, Y: 1}},
		Contour{Point{X: 4, Y: 2}, Point{X: 3, Y: 2}},
	}
	if !reflect.DeepEqual(r, want) {
		t.Errorf("%+v != %+v", r, want)
	}
}

func TestClipLine_within(t *testing.T) {
	tests := []struct {
		subject, clipping, want Polygon
	}{
		{
			subject: Polygon{{
				{-3999, -3999}, {-3500, -3500},
			}},
			clipping: Polygon{{
				{-4000, -4000}, {0, -4000}, {0, 0}, {-4000, 0}, {-4000, -4000},
			}},
			want: Polygon{{
				{-3500, -3500}, {-3999, -3999},
			}},
		},
		{
			subject: Polygon{{
				{X: 1.893757843025658e+06, Y: 358279.0127257189},
				{X: 1.893986642180132e+06, Y: 359465.8124818327},
				{X: 1.893983849777607e+06, Y: 359429.8946016282},
			}},
			clipping: Polygon{{{X: 1.89e+06, Y: 340000}, {X: 1.91e+06, Y: 340000}, {X: 1.91e+06, Y: 360000},
				{X: 1.89e+06, Y: 360000}, {X: 1.89e+06, Y: 340000}}},
			want: Polygon{{
				{X: 1.893757843025658e+06, Y: 358279.0127257189},
				{X: 1.893986642180132e+06, Y: 359465.8124818327},
				{X: 1.893983849777607e+06, Y: 359429.8946016282},
			}},
		},
	}

	for i, test := range tests {
		t.Run(fmt.Sprint(i), func(t *testing.T) {
			r := test.subject.Construct(CLIPLINE, test.clipping)
			if !reflect.DeepEqual(r, test.want) {
				t.Errorf("%+v != %+v", r, test.want)
			}
		})
	}
}